1. Field of the Invention
The invention relates to a device for the linear displacement of a valve member. The invention relates, furthermore, to the use of the device.
2. Prior Art
Valve members are known. DE 103 27 271 A1 describes a valve member for an additional control valve arrangement. In the valve member, on a shank, a cap-shaped disk is arranged, which is designed convexly with an apex toward the side facing away from the inlet valve. Such valve members are displaced linearly in the direction of the longitudinal axis of the shank as a function of the operating state of the valve. This takes place, as a rule, via a spindle drive, the spindle and the shank of the valve member having the same longitudinal axis. When relatively high forces act on the valve member during the operating phase, the load on the spindle increases considerably, and this may lead to the latter being damaged. Moreover, higher forces also act on the nuts which are attached on the spindle, and therefore these, too, may suffer damage.
U.S. Pat. No. 2,370,604 discloses a device for the linear displacement of a valve member that consists of a spindle rotatably mounted perpendicular to the direction of displacement, which consists of a first spindle part and of a second spindle part. The first and second spindle parts have external threads formed contradirectionally to one another. A first nut with a complementary internal thread is attached on the first spindle part and a second nut with a complementary internal thread is attached on the second spindle part. The first nut has a first bearing for the rotatable mounting of one end of a first connecting web perpendicular to the axis of rotation of the spindle and the second nut has a second bearing for the rotatable mounting of one end of a second connecting web perpendicular to the axis of rotation of the spindle. The other end of the first connecting web and the other end of the second connecting web are rotatably mounted jointly perpendicular to the axis of rotation of the spindle on a third bearing which is arranged on the stop for the valve member. The direction of displacement of the valve member, the middle of the third bearing, and the middle of the spindle always lying on a line L in the side view.